The present invention relates to a thermal processing apparatus for a band film, preferably used for embossing a carrier tape accommodating chip components.
In general, a thermal processing of a band film comprises a preheating of a portion of the band film by a heating unit and a succeeding embossing of the heated portion into a predetermined pattern by an embossing unit. The same pattern is continuously formed on the surface of the band film by repetitively applying the heating and the embossing on the band film advancing with a predetermined pitch.
In such a thermal processing apparatus repeating the same sequential operations, a higher productivity is realized by reducing the time required for accomplishing one cycle of the thermal processing. To this end, it is desirable to locate the heating unit adjacent to the embossing unit.
As the band film advances with the same pitch and the same timing when the thermal processing is continuously performed, the temperature of the next processed surface of the band film is stably increased to substantially the same value.
However, a problem arises when the thermal processing is interrupted or stopped because a portion of the band film located immediately before the embossing unit is subjected to high temperature of the heating unit for a long time. This will excessively increase the temperature of the first processed portion of the band film in the resumed thermal processing.
Furthermore, the heat radiated from the heating unit will possibly deform or shrink a finished embossed portion of the band film staying at the embossing unit located adjacent to the heating unit during a dormant period of the thermal processing apparatus.